Re: [PATCH v2] zram: Prevent page allocation failure during zcomp_strm_alloc

Sergey Senozhatsky
2015-11-21T02:14:46Z

On (11/21/15 11:10), Sergey Senozhatsky wrote:
> Cc Andrew
>
> On (11/20/15 19:02), Kyeongdon Kim wrote:
> > When we're using LZ4 multi compression streams for zram swap,
> > we found out page allocation failure message in system running test.
> > That was not only once, but a few(2 - 5 times per test).
> > Also, some failure cases were continually occurring to try allocation
> > order 3.
> >
> > In order to make parallel compression private data, we should call
> > kzalloc() with order 2/3 in runtime(lzo/lz4). But if there is no order
> > 2/3 size memory in that time, page allocation fails.
> > This patch makes to use vmalloc() as fallback of kmalloc(), this
> > prevents page alloc failure warning.
> >
> > After this, we never found warning message in running test, also
> > It could reduce process startup latency about 60-120ms in each case.
>
> Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
>

with the only nit that the subject should be "try kmalloc() before vmalloc()"
or similar, not "prevent page allocation failure", I think.

-ss